MITSMI MM1548 Datasheet
MITSUMI
Secondary Control for Energy-Saving AC Adaptor MM1548
Secondary Control for Energy-Saving AC Adaptor
Monolithic IC MM1548
Outline
This IC is secondary control on AC adaptors that have energy-saving mode. The energy-saving mode
function operates when charging is completed or when the set is unplugged, thus greatly reducing AC
adaptor power consumption.
When a set is connected, normal mode automatically starts and charging starts.
Compared to the conventional MM1529, this IC is smaller and has fewer external components.
Features
1. Automatic switching between energy-saving mode and normal mode
2. Current consumption (energy-saving mode) 60µA
3. Current consumption (normal mode) 1.5mA
4. Uses one photocoupler to control oscillator primary side.
5. One photocoupler is used to control rated voltage and rated current and switching between energy-saving
and normal modes.
Package
SOT-26
MITSUMI
Pin Assignment
1 6
2 5
3 4
SOT-26
1 OUT 4 PO1
2 CNT 5 GND
3 V
CC 6 CS
MITSUMI
Secondary Control for Energy-Saving AC Adaptor MM1548
MITSUMI
Block Diagram
GND
5
CS
6
PO1
4
VCC
3
CNT
2
OUT
1
COUT
ROS1
ROS2
RCS
Constant current detection resistor
(CS=34mV)
Reference voltage decrease (drop)
Constant current control
(CS=114.4mV)
Constant voltage control
(V
CC=5.1V)
Load detection(voltage)
(V
CC=3.5V)
Over voltage
detection
(7V)
5k
Load detection(current)
(115mV 200mV)
Input/output difference control
(VCC-OUT=200mV)
Voltage bufferPhotocoupler-turn-off
Primary-side switching
control
RLS
Load detection resistor
RLB
VCC
1.25V
Reference voltage
PC1
RL1
transformer secondary side
VCC=4.6V
MITSUMI
Secondary Control for Energy-Saving AC Adaptor MM1548
Pin Description
Pin No. Pin Name Function Internal equivalent circuit
1 OUT
Output (+) pin.
Connect Registor for load detection
between V
CC pin, and connect collector
of PNP power transistor.
VCC
1
2
1.25V
3
4
6
VCC
2 CNT PNP power transistor control pin.
Connect base of PNP power transistor.
4 PO1 Photo diode drive pin of photocoupler
for constant-current and constant-
voltage control.
Connect to cathode of diode.
5 GND Ground pin of this IC.
6 CS Overcurrent detection pin.
This pin doubles as output- pin.
Connect Resistor for overcurrent
detection between GND pin.
3 V
CC (+) power supply pin.
This pin doubles load detection pin.
Connect load detection resistor
between OUT pin, and connect emitter
of PNP power transistor.
MITSUMI
Secondary Control for Energy-Saving AC Adaptor MM1548
Absolute Maximum Ratings
(Ta=25°C)
Recommended Operating Conditions
Electrical Characteristics
(unless otherwise specified, Ta=+25°C, Vcc=4.9V)
Item Symbol Ratings Unit
Storage temperature T
STG –40~+125 °C
Operating temperature T
OPR –30~+85 °C
Supply voltage V
CC max. –0.3~+18 V
Allowable loss Pd 150 (alone) mW
Item Symbol Ratings Unit
Operating temperature T
OPR –30~+85 °C
Supply voltage V
OP +2.5~+12 V
Item Symbol Test Conditions Min. Typ. Max. Unit.
Current consumption1(energy saving mode)
I
CC1 VCC=4.4V, VOUT=4.4V, VCS=0V 60 110 µA
Current consumption2(normal mode)
ICC2 VCC=5.3V, VOUT=5.0V, VCS=0V 1.5 3.0 mA
Voltage control section
Output inversion voltage V
O IIN=5mA, VOUT=VCC–0.3V, VCS=0V 4.99 5.10 5.21 V
OUT input sink current I
OUT VCC=4.9V, VOUT=4.9V, VCS=0V 25 150 nA
PO1 output sink current 1 I
PO1 VCC=5.3V, VOUT=5.0V, VCS=0V VPO1=0.5V 5 17 mA
Constant current control
Output inversion voltage 1
V
CS1
VCC=4.9V, R
CS1
=1kΩ, V
OUT
=4.6V, R
CS2
=40kΩ, IIN=5mA
111.2 114.4 117.6 mV
(Constant current control)
Output inversion voltage 2
V
CS2
VCC=2.0V, R
CS1
=1kΩ, V
OUT
=0V, R
CS2
=40kΩ, IIN=5mA
22 34 mV
(Constant current control drop)
CS input source current ICS VCC=4.9V, VOUT=4.6V, VCS=0.1V 5 100 nA
Power supply voltage rejection ratio
PSRR2
VCC=3.7V 4.4V, VCS=V
CS1
–10mV, RL1=5kΩ
60 70 dB
PO1 output sink current 2 I
PO2 VCC=4.9V, VOUT=4.6V, VCS=0.2V, VPO1=0.5V 5 17 mA
Input-output difference control
Input-output difference control voltage
V
LS VCC=5.1V, RLS=4.7kΩ, RLB=100Ω, RO=5kΩ 140 200 260 mV
CNT output sink current I
CNT VCC=5.1V, VOUT=4.8V, VCS=0V, VCNT=0.8V 5 30 mA
Load detection
Load detection voltage V
LSP1
VCC=4.9V, RL1=47kΩ, V
OUT
=4.9V L, VCS=0V
170 200 230 mV
Energy saving detection voltage
V
LSP2
VCC=4.9V, RL1=47kΩ, V
OUT
=L 4.9V, VCS=0V
85 115 145 mV
(load detection release voltage)
3.5V undervoltage detection VOL1 VCC=H L, RL1=10kΩ, VOUT=VCC, VCS=0V 3.4 3.5 3.6 V
3.5V undervoltage detection hysteresis
VOL1H VCC=L H, RL1=10kΩ, VOUT=VCC, VCS=0V 350 mV
4.6V undervoltage detection V
OL2 VCC=H L, RL1=47kΩ, VOUT=VCC, VCS=0V 4.47 4.60 4.73 V
PO1 output sink current 3 I
PO3 VCC=4.9V, VOUT=4.6V, VCS=0V, VPO2=1.0V 100 200 400 µA
PO1 output source current I
PO4 VCC=4.9V, VOUT=4.9V, VCS=0V, VPO2=4.6V 1.0 5.0 mA
Constant current mode selection
2pin(CNT pin) disable voltage V
CNTO
VCC=H L, V
CNT
=0.8V, V
OUT=VCC
–0.3V, VCS=0V, I
CNT
< 1mA
2.4 V
Constant current mode selection threshold
VCSS
VCC=4.9V, R
CS1
=1kΩ, V
OUT
=4.6V, R
CS2
=20kΩ, IIN=5mA, V
CS
< V
CS
min.
0.6 V
(between V
CC and OUT)
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